Optical codes are often used for transmitting data. For example, an optical code scanner can read data encoded in a bar code or in a Quick Response (QR) code. However, at least some types of optical codes require relatively long read-times. Some optical code technologies allow for a relatively narrow range of positions and angles at which a code and a reader must be placed relative to each other. It is sometimes also necessary for an optical code reader to first focus on the object bearing the optical code.
EP1705595A2 describes a system that transmits password information as a password motion picture signal. The password motion picture signal changes its uniform color of a frame at a predetermined frame interval according to the password information.